Genetics Basics

Genetics

Key Concepts

• Genetics: the study of heredity, genes, and genetic variation
• Genome: the complete set of genetic information in an organism
• Gene: a unit of heredity that carries information from one generation to the next
• Trait: a characteristic or feature of an organism

DNA Structure and Replication

• Double Helix Model: DNA is shaped like a twisted ladder with two complementary strands
• Nucleotides: building blocks of DNA, consisting of sugar, phosphate, and nitrogenous bases
• Base Pairing: A-T and G-C pairing rules

Gene Expression

• Transcription: the process of creating a complementary RNA copy from a DNA template
• Translation: the process of building a protein from an RNA sequence
• Codons: sequences of three nucleotides that code for amino acids

Inheritance Patterns

• Mendel's Laws:
  • Law of Segregation: each pair of alleles separates during gamete formation
  • Law of Independent Assortment: alleles of different genes are sorted independently
• Dominant and Recessive: alleles with different effects on the phenotype
• Incomplete Dominance: when neither allele is completely dominant

Genetic Variation

• Mutations: changes in the DNA sequence
• Genetic Drift: random events that change allele frequencies
• Gene Flow: movement of genes from one population to another
• Natural Selection: the process by which populations adapt to their environment

Genetics

Key Concepts

• Genetics is the study of heredity, genes, and genetic variation, which explains how traits are passed from one generation to the next.
• The genome is the complete set of genetic information in an organism, containing all the genetic material needed to create and sustain life.
• A gene is a unit of heredity that carries information from one generation to the next, and is made up of a sequence of DNA nucleotides.
• A trait is a characteristic or feature of an organism, such as eye color, height, or skin color, which is determined by the interaction of genes and environment.

DNA Structure and Replication

• The double helix model of DNA is shaped like a twisted ladder, with two complementary strands that are held together by hydrogen bonds between nucleotides.
• Nucleotides are the building blocks of DNA, consisting of a sugar molecule, a phosphate group, and one of four nitrogenous bases - adenine (A), guanine (G), cytosine (C), and thymine (T).
• The base pairing rules of A-T and G-C are crucial for the replication of DNA, ensuring that the sequence of nucleotides is preserved during cell division.

Gene Expression

• Transcription is the process of creating a complementary RNA copy from a DNA template, allowing the genetic information to be used in the synthesis of proteins.
• Translation is the process of building a protein from an RNA sequence, where codons (sequences of three nucleotides) specify the sequence of amino acids.
• Codons are sequences of three nucleotides that code for one of the 20 amino acids, which are the building blocks of proteins.

Inheritance Patterns

• Mendel's laws of inheritance, including the law of segregation and the law of independent assortment, describe how alleles are passed from one generation to the next.
• The law of segregation states that each pair of alleles separates during gamete formation, resulting in each gamete receiving only one allele.
• The law of independent assortment states that alleles of different genes are sorted independently during gamete formation, resulting in a random combination of alleles.
• Dominant and recessive alleles have different effects on the phenotype, with dominant alleles masking the effects of recessive alleles.
• Incomplete dominance occurs when neither allele is completely dominant, resulting in a combination of the effects of both alleles.

Genetic Variation

• Mutations are changes in the DNA sequence, which can occur spontaneously or as a result of environmental factors, and can result in changes to the phenotype.
• Genetic drift is the random change in allele frequencies over time, which can result in the loss of genetic variation in a population.
• Gene flow is the movement of genes from one population to another, which can increase genetic variation and reduce the effects of genetic drift.
• Natural selection is the process by which populations adapt to their environment, where individuals with favorable traits are more likely to survive and reproduce, passing on their advantageous alleles to the next generation.